Content displayed on web pages can be generated by one or more content servers in response to content requests. Publishers can embed content-server specific tags in web pages in order to serve content (e.g., ads) to their visitors from the content servers. Tags are used to describe what content slots exist in a given web page and what creatives can be served to each slot. Content may not appear in a given web page at the time for rendering due to network latencies, typographical errors in the tag names, and mis-configurations. For example, the tags may be incorrectly or incompletely specified, or correctly specified tags may not match the server-side settings. In addition, content presentation may fail due to client browser or operating system problems, locale or language issues, transient networking issues and the like.
When errors occur, a publisher typically will make a service call, which are time consuming and expensive to the content server provider. In many instances, the content server provider may have difficulty reproducing the underlying problem that causes an error. For example, the cause of the problem may be an older browser or non-supported version of an operating system. Transient network problems are also difficult to reproduce, which makes it difficult for the content server provider to diagnose the problem.